12 Dunsford Place, Bathwick, Bath

12 Dunsford Place forms part of a Grade II early 19th century terrace situated within the Bath conservation area and World Heritage Site. It forms part of the setting of the Grade II early 19th century terrace at George Street, as well as the Grade II mid-19th century detached villa Miles House which is visible in the wider, sweeping east-west views along Bathwick Hill towards Raby Place. It forms part of the typical Georgian vernacular along Bathwick Hill in its use of Bath stone ashlar, natural slate or clay pantiles, and timber sash windows, with 12 Dunsford Place retaining its traditional-style six-over-six pane sash windows in keeping with the wider terrace. There is some unusual variation in roof articulation, with a mix of double-M roofs and pitched rear roofs that run into the street-facing roof slope. Due to the continuous run of roof slope towards the front-facing eaves from the rear roof ridge at 12 Dunsford Place, the roofscape is of increased visibility and requires more sensitive consideration about how change could be integrated.

In the light of the declared Climate Emergency BPT is generally supportive of retrofit measures that protect elements that contribute to the special architectural and historic interest of a listed building; alterations are expected to be visually coherent with the character of the building, and the wider shared character of the listed terrace and surrounding conservation area.

We are supportive of the principle of the wholescale installation of slimlite glazing, where this is sensitively integrated with the special historic and architectural interest of a listed building and the wider character and appearance of the conservation area, although the suitability of energy-efficient retrofits in relation to heritage significance, effectiveness, and the risk of unintended consequences must be assessed on a case-by-case basis.

We acknowledge that the existing windows are non-historic in origin. This offers a positive opportunity for the implementation of energy-efficient retrofits without the loss of historic fabric.

However, it is unclear as to the proposed scale of works and whether this would include both the front and rear elevations of the building. The existing/proposed sash window details provided appear to only relate to the larger sash typology of the first floor windows on the front elevation. BPT therefore strongly recommends that the scope of works is clarified and any additional sash window details or dimensions are included for the benefit of the case officer.

In this particular case, BPT recognises that the installation of slimlite glazing would result in less than substantial harm and no loss of historic fabric. A wholescale installation of slimlite glazing across the front elevation is recommend to ensure a consistent appearance and finish to more effectively mitigate potential visual harm. The proposals would result in the loss of non-historic glazing, and would retain the existing timber sash frame with minimal visual alterations to the existing glazing bar thickness or profile, although we note the depth of the glazing bar would be reduced from 29mm to 20mm to accommodate the additional glazing thickness. We recommend that the viability of retrofitting the existing timber sash frames is clarified as part of the application to ensure minimal change to the appearance or character of a listed building.

BPT is very interested in working with the applicant to get a better understanding of the existing and proposed window condition and design. We feel that this scheme can provide an invaluable opportunity to monitor the thermal and acoustic efficiency of the windows, before and after, whilst also observing any additional repercussions such as changes in humidity levels. This information could then be used to more accurately assess the suitability of slimlite installation in Bath’s historic building stock and create a best practice example that would help further future retrofits to buildings of historic significance within Bath.

We are generally supportive of the installation of PV panels where this would not significantly compromise historic fabric or the distinctive character and appearance of the historic environment. However, due to the unusual roof profile of 12 Dunsford Place, we do have some concerns regarding visibility in wider streetscape views. Therefore, we strongly recommend that further design details of the proposed panels are submitted as part of this application to ensure a non-intrusive appearance and finish in accordance with Policy SCR2 of the Core Strategy and Placemaking Plan. We suggest that PV panels should be monochrome with a matt finish to minimise reflectivity and associated sun glare, and should sit as flush with the roof slope as possible.